The article is a few months old, but more research continues to be done. Here is an excerpt about a research paper that will be released soon:

Hearing loss is associated with accelerated cognitive decline and possibly also with the onset of dementia in older adults. The vast majority of scientists in the area have agreed that cognitive decline is likely related to the lack of social interaction that older adults have because of their hearing loss.

A new study, “Self-Reported Hearing Loss: Hearing Aids and Cognitive Decline in Elderly Adults: A 25-year Study”, just published in the Journal of the American Geriatrics Society, compared the trajectory of cognitive decline among older adults who were using hearing aids and those who were not. The study found no difference in the rate of cognitive decline between people with no reported hearing loss and people with hearing loss who used hearing aids. 